System Freezes - Everything looks connected though

I have a system running FreePBX13, Asterisk 13.18. Every 3-4 weeks all the phones lose connection to the FreePBX. No extension to extension calls and no calls register coming in from the SIP Trunks. Inside the Asterisk info though every phone appears to be registered as do the SIP Trunks. If I run an update from say 13-21 to 13-22 the system comes back to life. If I run an asterisk update (I went from 13.17 to 13.18) the system comes back to life also. Any ideas or thoughts would be helpful as the problem comes and goes with no seeming trigger.

Update - In the Asterisk Info it appears that there are active sip channels which is not true

Using chansip or pjsip?


Also - rebooting the phones does nothing, DNS seems fine as well